Side booms



SIDE BOOMS 2 Sheets-Sheet 1 Filed May 23, 1958 INVENTOR.

FIG.3

SAMUEL L. TODERICK TORNEYS Oct. 24, 1961 s. L. TODERICK SIDE BOOMS 2 Sheets-Sheet 2 Filed May 23, 1958 INVENTOR.

SAMUEL L. TODERICK TTORNEYS 3,005,559 SIDE ROOMS amnel L. Toderick, Welland, Ontario, Canada, assignor to .iohn Deere llow Company (Limited), Welland, Ontario, Canada, a corporation of Canada Filed May 23, 1958, Ser. No. 737,416 4 Claims. (Cl. 212-8) The present invention relates generally to mobile hoists and is more particularly concerned with machinery of this character that is adapted to be mounted on a farm or industrial tractor.

The objects and general nature of this invention is a provision of a new and improved side boom attachment for tractors in which means is provided for terminating the raising of the boom as it approaches a vertical position so as to prevent the imposition of excessive stresses on the frame or other parts of the attachment against which the boom may be brought if its upward travel is not properly controlled. More particularly, it is a feature of this invention to provide, in equipment of the above described character, means of the nature of bumper springs or other resilient means so constructed and arranged to serve as a resilient stop for the boom as it approaches its vertical or uppermost position, and a further feature of this invention is the provision of means associated with such boom arresting means for terminating the application of power to the boom elevating means so that the power is cutoff as the boom approaches its uppermost position.

A particular feature of this invention lies in the combination with hydraulically actuated boom-raising means of means in the nature of a bypass means actuated by movement of the boom as it approaches its upwardmost position for reducing the flow of fluid under pressure to the boom raising mechanism so that effective operation of the latter in the raising direction is terminated.

These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a vertical elevation of the side boom and its attaching frame structure, the parts being shown as mounted on a tractor of the crawler type.

FIG. 2 is a fragmentary enlarged view of the power terminating mechanism.

FIG. 3 is an explanatory showing of certain of the hydraulic operating mechanism which has been illustrated more or less diagrammatically.

FIG. 4 is an enlarged sectional view showing the details of the limit or by-pass valve.

Referring first to FIG. 1, the tractor is indicated in its entirety by the reference numeral and is shown by way of illustration as a crawler tractor having crawler treads 11, the frames 12 of which receive and serve as supporting means for the main frame 15 of the side boom attachment. The side boom itself is indicated by the reference numeral 17 and comprises an A-frame made up of two channel members 19 and suitable braces, including a cross angle 21. The boom 17 is pivoted at 22 to associated pairs of lugs 23 that are fixed to an attachment angle 24 that is adapted to be bolted or otherwise fixed to the associated track frame 12.

The boom 17 is raised and lowered by a cable connection 25 that is dead-ended by clevis 26 pivoted to a portion of the frame 15. The cable is passed around a sheave 28 at the upper end of the boom and then is brought downwardly to a drum 29 that forms a part of the boom winch 3%). The latter is driven by a boom motor 31 in the form of a hydraulically driven unit,

States Patent operation of which is derived from a pump 32 (FIG. 3) or other means carried on the tractor 10". Suitable controlling valve mechanism indicated diagrammatically at 35 is so constructed and arranged that hydraulic operating pressure can be directed to the boom motor 31 through either of the associated pressure lines 36 and '37. Hydraulic mechanism of this kind is generally convention-al so far as this invention is concerned.

According to the present invention means is provided for automatically terminating the application of effective power to the boom motor 31 when the boom 17 approaches its uppermost position, and such mechanism will now be described.

Mounted on the boom 17, preferably on the cross angle 21 thereof, is an abutment member 41 that is adapted to engage the upper end of a boom arresting spring unit 42 bolted, as at 43, to a portion of the arch making up the frame 15. The unit 42 preferably is made up of two or more leaf springs, and connected to one of them is an apertured lug '45 to which one end of a cable 46 is connected, as by a hook type adjustable connector 48. The other end of the cable, which is extended through a protecting sheath 49, is connected to a limit valve unit 50.

As best shown in FIG. 4, the limit valve 50 includes a casing 51 in which a valve plunger 52 is slidably disposed. The valve housing 51 is provided with an interior chamber 53 with which two passageways 54 and 55 are in communication. The pressure lines 36 and '37 are connected, respectively, with said passageways, as by conduit extensions 36a and 37a. The plunger 52 is provided with an annular chamber or other suitably formed cavity "58, that in one position of the plunger 52, places the two passageways 54 and 55 in communication with one another. As will be seen from FIG. 4, the valve plunger is normally disposed in a second position in which a land 59 on the plunger 52 cuts off communication between the passageways 54 and 55.

When the limit valve parts are in this second position (FIG. 4) full operating pressure from the pump 32 (FIG. 3) is exerted upon the boom motor 31 in either position of the operating valve mechanism 35. A spring 61 is disposed about the outer end of the plunger 52, bearing against an abutment washer 62 that is fixed to the outer end of the plunger 52, the other end being connected in any suitable way to the inner end of the cable 46.

In operation, when the boom approaches its uppermost position and comes into engagement with the arresting or cushioning springs 42, slight additional movement of the boom shifts the springs 42 and relaxes the pull thereof on the cable 46, whereupon the spring 61 shifts the plunger 52 a certain amount to the right, as viewed in FIGS. 2 and 4; as determined by a stop abutment 63 (FIG. 4) on the other end of the valve plunger 52. This opens communication between the passageways 54 and 55 and as a result a suflicient flow of fluid from the high pressure side to the low pressure side of the pump connections 36 and 37 is diverted around the boom motor 31 so that it no longer delivers enough power to further raise the boom. The connection 4-8 is so adjusted that in the unstressed position (FIG. 1) of the boom arresting springs 42, the latter exert sufficient force through the cable 46 to hold the plunger 52 in a closed position (FIG. 4) in which communication between the passageways 54 and 55 is shut 011.

Thus, when opened, as described above, the limit valve unit 50 is in the nature of a restricted conduit or connection between the high and low pressure leads acting to prevent a full power flow of hydraulic fluid between the pump and motor, so that the boom will not be raised,

but nevertheless there is a sufficient flow of hydraulic fluid to the boom motor to exert enough power to operate the motor 31 in the boom-lowering direction, whenever the controlling valve mechanism 35 is reversed from raising to lowering. Thus even though the limitflvalve 50 is open the motor 31 can bedriven, with enough effective force to move the boom away from the arresting springs '42 which then permits the springs 42 to shift the limit valve into its closed position. After this occurs, full power may then be applied to the boom motor 31 in either the raising or lowering direction, as desired. While have shown and described above the preferred structure in which the principles of the present invention have been incorporated, it is to be understood that my invention is not to be limited to the particular details shown and described above, but that, in fact, widely different means may be employed in the practice of the broader aspects of my invention.

What I claim, therefore, and desire to secure by Letters Patent is:

1. The combination, in a tractor mounted hydraulic side boom, of a vertically swingable boom, a tractor carried frame upon which said boom is pivoted, a winch motor, means connecting the latter to said boom to raise and lower the latter, a hydraulic pump, fluid connections between said motor and pump, a limit valve connected with at least one of said connections for diverting some but not all of the fluid from said winch motor to terminate raising movement of said boom and means connected to be actuated by movement of said boom as it approaches its upper position for operating said limit valve.

2. The combination, in a tractor mounted hydraulic side boom, of 'a vertically swingable boom, a tractor carried frame upon which said boom is pivoted, a winch motor, means connecting the latter to said boom to raise and lower the latter, a hydraulic pump, fluid connections between said motor and pump, a limit valve connected with at least one of said connections for diverting some but not all of the fluid from said winch motor to terminate raising movement of said boom, a spring biased part movably mounted on said frame in a position to be engaged by said boom as it approaches its upper position for yieldab'ly opposing further raising movement of the boom, a connection between said spring biased part and said limit valve for operating the latter, and means on 4 said boom to engage said spring biased part and move the latter so as to actuate said valve.

3. A tractor mounted side bcxam attachment adapted to be mounted on a crawler type tractor, said attachment comprising a generally U-shaped frame adapted to straddle the tractor and having lower sections carried by the tractor, a boom comprising an A-frame pivotally supported on the tractor and straddling the adjacent lower section of said frame, a generally vertically disposed spring carried by the interior port-ion of said adjacent lower frame section, the latter having an opening through which the upper end of said spring extends, means on the A-frame to engage said end of the spring to yieldingiy oppose further upward swinging of the boom, controllable power means to raise said boom, and means connected with the end portion of said spring and with said power means to terminate the application of raising power to said boom when said spring end moves, said spring comprising a plurality of generally vertical leaves fixed at their lower ends to said lower frame section, and a lug fixed to the upper end of said spring and forming a part of the means connecting said spring with said power means. a

4. The combination, in a tr ctor mounted side boom, of a vertically swingable boom, power means connected to raise said boom, and including a power control means having means biased to move into a reduced power position and movable into another position in which full power may be transmitted to the boom to raise andlower the latter, stop means for the boom for defining the upper limit of boom movement, comprising a spring member engageable by said boom as the latter approaches its upper position and serving to arrest the movement of the boom, said spring means being capable of exerting snfiicient force to overcome the bias of said power control means whereby when the boom is out of contact with said spring means the latter serves to shift said power control means into a full power position.

References (Iited in the file of this patent UNITED STATES PATENTS 1,443,376 Morgan Jan. 30, 1923 2,013,690 Lamond Sept. 30, 1935 2,376,019 Thomas May 15, 1945 2,712,873 Peterson July 12, 1955 2,885,092 Murrey May 5, 1959 

